Sprint recompression of JPEG files

Update, 2014-10-25: This can be mitigated on the server side. When HTTP
headers specify 'Cache-Control: no-transform', Sprint's proxy honors it and
doesn't degrade the image before sending it to the phone. In apache, this can
be achieved by enabling mod_headers and putting Header add Cache-Control
no-transform in an appropriate location. I've done this for the server where
my photos come from...

When showing my blog photos on my phone, I noticed that they looked terrible.
Shown above is a detail of the original image (not entirely free of JPEG
artifacts) and of the same area after it was recompressed by sprint.
(zoomed 200%, nearest neighbor scaling)

It turns out that sprint recompresses jpegs and this is documented by sprint, but
it's still terrible.

It also affects ting.com users, since they are a sprint reseller. (and I didn't find any ting documentation about this misfeature yet)

This happens both on the phone itself, and to devices tethered via the phone.

Most images aren't mangled quite as badly as this one, but their claim that
there's "no user perceptible loss of quality" is bunk.